In view of the increasing load of cellular communication networks, it has been proposed to let cellular communication networks use unlicensed spectrum. For example, for LTE (Long Term Evolution), LTE-LAA (Licensed Assisted Access) and LTE-U (LTE in unlicensed spectrum) have been proposed for the use of 4G LTE communication in unlicensed spectrum such as the 5 GHz band used by dual-band WiFi devices. Efficient approaches for the usage of a frequency range in unlicensed spectrum for communication are desirable.